


Shared Characteristics

by SailorChibi



Category: Miraculous Ladybug
Genre: Comedy, F/M, Fluff, Identity Reveal, Mating Cycles/In Heat, No Angst, Poor Marinette, mentions of safe sex, no actual sex occurs within the fic
Language: English
Status: Completed
Published: 2018-10-22
Updated: 2018-10-22
Packaged: 2019-08-06 04:18:43
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,895
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16381247
Author URL: https://archiveofourown.org/users/SailorChibi/pseuds/SailorChibi
Summary: Out of all the things Nino and Alya could've inherited from their kwamis, it would be a heat.





	Shared Characteristics

For once, Marinette was the first of her friends to make it to school. She took up a spot near the steps and rubbed her hands together, wishing she'd thought to grab a coffee on her way out of the bakery. Or gloves. It was definitely brisk enough to warrant them, the early morning chill proof that summer was on its last legs.

"Uggggh." The long, drawn-out moan was the only warning Marinette got before a forehead hit her back. She peered over her shoulder.

"Are you okay, Alya?" she asked.

"Yeah," Alya mumbled. "No. I don't know. I've been feeling weird for the past couple days."

Marinette turned around to get a better look at her friend. Alya's face was flushed, and perspiration was beading at her temples. She frowned in concerned. "You don't look good. Maybe you should've stayed home."

"And deal with my little sisters all day? That would just make me feel worse." Alya sighed and folded her arms across her belly. "It's not like a cold or something like that. I feel hot and kind of restless."

"Restless?"

Alya glanced around, then leaned in. "Horny. I'm _really_ horny."

"I... oh." Marinette blushed a little. "Maybe you should go... you know."

"I did. Multiple times. I think my fingers are permanently wrinkled." Alya made a face. "It's not helping. I've soaked more underwear in the past three days..."

Warning bells began to chime in the back of Marinette's head. All of this was sounding a little too familiar. She studied Alya a little more closely. "Ok, awkward question, have you been feeling really... um... empty?"

"Yes!" Alya exclaimed. "Oh my god, how did you know?"

"Lucky guess," Marinette muttered. Oh shit. Oh _shit_.

"Anyway it's probably just my period coming or something like that. It'll go away," Alya said, rolling her shoulders. "I just have to wait it out."

"Um, Alya -"

"Hey, look, there's your boyfriend," Alya interrupted.

THANK. GOD.

"StayhereI'llberightback!"

Marinette dashed across the schoolyard. Adrien was just stepping out of the car. It was fortunate that he saw her coming, as her flying tackle probably would've sent them both to the ground otherwise. Instead he caught her with ease, automatically spreading his feet and bracing himself to absorb her weight.

"Hi Princess," he said with a cute grin. "I missed you too."

"We have a problem," Marinette hissed, putting her hands on his shoulders and shoving her face up near his ear. "A REALLY BIG problem we need to talk about now. Privately."

His smile had faded when she pulled away, turning serious. Without a word he took her hand and they scuttled around the far corner of the school. There were some trees there, but it was directly in the wind so most students didn't go there. Marinette peeked back around the corner to see a bemused Alya still standing where Marinette had left her.

"My Lady?"

"I think Alya is going into heat," Marinette burst out, spinning around to face him.

Adrien's mouth dropped open. As he processed her words and got over the initial shock, a look of horror set in. "What - how -"

"I don't know." Marinette grabbed her pigtails and tugged, trying to contain a shriek. 

They'd been down this road before. Four months ago, Marinette had her 17th birthday just a couple months after Adrien had had his. Neither one of them had been expecting what followed. It turned out that once both Ladybug and Chat Noir had reached their sexual maturity, they went into heat.

That would forever stand out as one of the most awkward weeks of Marinette's life. First the conversation with Tikki. Then the talk with Chat Noir. Then the couple days where they'd tried to handle things separately. She could still remember that awful feeling; like she was burning from the inside out, a pain in her core that nothing could extinguish. It sounded dramatic now, but at the time she'd thought she might be dying.

Chat Noir had been struggling too, it turned out. Enough so that, when she called him up to meet and then promptly jumped him on a Parisian rooftop, the kitten had eagerly pinned her down and fucked her. Finding out who your partner was while you were being fucked by them wasn't really recommended, just for the record.

The following five days had been spent dodging their families and responsibilities while fucking as much as humanly possible. Thank god no akumas had come around, as she wasn't actually sure they would've been able to pry themselves apart to deal with it - and the Ladyblog did not need footage of Ladybug trying to climb Chat Noir in the midst of an akuma battle.

"Is that..." Adrien's voice sounded strangled. "I mean... how. She's only been Rena Rouge a couple of times!"

"It only takes once," Plagg volunteered, poking his head out of Adrien's shirt pocket. "The more you transform, the deeper the bond."

"So I'm right," Marinette said, heart sinking.

Her purse snapped open and Tikki stuck her head out. "You're right, Marinette. I could smell it. Alya's heat is very close. She'll go into full heat once she's in proximity to her partner, just like you did."

Marinette stared at her for a moment. Then her head shot up and she stared at Adrien, seeing her horrified look perfectly replicated on Adrien's face.

Nino.

"SHIT."

They both made a mad dash for the front of the school. There was no sign of Nino yet, thank god. Marinette didn't even know if turtles went into heat, but she knew that Nino had to be Alya's partner. It sure as hell couldn't be Chloé.

"What do we do?" Adrien said, sounding frantic.

"Okay. Okay." Marinette grabbed his face, pulling it closer to hers. "Go buy the biggest pack of condoms you can find. Alya's not on birth control like I was, and this is going to be awkward enough as it is."

Because she knew that Alya and Nino would not have the sense to go buy their own condoms. Not if their heat was going to be like anything she and Adrien had gone through. It was sheer luck that Marinette had been on the pill for years to help with her periods when she went into heat; the thought of birth control hadn't even crossed her mind until they'd already fucked a half dozen times.

"Condoms. I can do that. Then what?"

"Hotel?" Marinette said uncertainly. They'd made do, spending all their nights at Adrien's. But Nino and Alya wouldn't have the luxury of a mostly empty house.

He blinked at her, looked over at Alya, then said, "I'll get the condoms and book a room. I'll text you the address. Bring them both."

"I will." Marinette paused, her hands started to shake. "We're going to have to... to tell them."

Adrien's hands came up and covered hers. He pulled them away from his face and pressed a kiss to both her knuckles. "It will be okay, Bugaboo," he whispered. 

Marinette wasn't so sure about that, but she tried to believe him. She nodded and tried to smile. Adrien kissed her cheek and then took off, running towards the gates. Marinette walked back over to Alya, doing her best to pretend that everything was normal. Judging by the wide eyed look Alya was giving her, she was failing spectacularly.

"What the hell was that?" Alya said.

"Nothing. Um. How do you feel about skipping school today?"

Alya narrowed her eyes. "Skipping? Why?"

There was only one thing that would get Alya to agree. "Adrien and I figured out something about Ladybug, but we can't show you here. Too many people."

"What did you find out?"

"I can't tell you here," Marinette said. She crossed her fingers as Alya's curious frown deepened. 

"Fine," Alya said after a noticeable pause. "But this better be good."

"Oh, believe me. You're going to freak," Marinette said, linking their arms together. Out of the corner of her eye, she noticed Nino walking in. It was kind of like a magnet: Alya wasn't even looking in his direction, but the instant Nino was about approximately twenty feet away her head snapped around and she stared directly at him. Marinette tightened her grip. She remembered this, too. During their heat, she'd been hyper aware of Adrien's presence at all times. It was something that had never really faded, and which wasn't that unusual for them as Ladybug and Chat Noir - but it was totally out of the norm for Alya and Nino.

"Wow," Alya said to no one in particular. "Nino looks... Nino looks awesome today." Her lips parted and she slowly drew her tongue across her bottom lip.

"Yeah, he's alright. Come on." She gently pulled Alya, and, because they were going in the direction of Nino, Alya came along willingly. Nino met them halfway. His eyes were locked on Alya. They reached for each other.

Marinette stepped in between. If they got a hold of each other now, clothes would start flying off. "Hey! Let's go for a walk!" she shouted, forcibly pushing them apart. 

"I - what?" Nino blinked. "Oh hey, Marinette. When did you get here?"

"Just now," Marinette said dryly. She linked her free arm through Nino's and dragged them both along, keeping herself firmly in the middle. She was pretty sure she knew which hotel Adrien would end up at; it was the same one he'd booked for them one night after a solid seven days of akuma attacks. They'd needed somewhere to just crash without being bothered.

"I feel weird," Alya whispered.

"Me too," Nino said. "But you look ravishing, Alya."

"Really?" Alya said, peering at him over Marinette's head.

Nino nodded, eyes glazing slightly. "I just wanna - wanna peel your shirt off and -"

"OKAY," Marinette said loudly. "I don't need a play-by-play of what you guys wanna do to each other, thanks." It probably wasn't her imagination that the heat radiating off of them seemed to be getting stronger. She picked up the pace.

"I could take my shirt off," Alya said eagerly, like Marinette hadn't even spoken. "I'm wearing that green bra you said you liked. The one I sent you a picture of? It makes my boobs look phenomenal."

"And your underwear?" Nino breathed, like he didn't dare hope.

"I bought the matching pair," Alya said, her voice deep and throaty. "It's a thong. Wanna see?"

"Nino, NO." Marinette pivoted, placing the flat of her hand over Nino's face and shoving him back. 

"But underwear!" Nino said, trying to fight against her. It was a laughably pathetic attempt, really. Not only was Marinette way stronger than your average teenager, Nino was half-drunk on heat lust.

"You can see it later. Once we get to the hotel," Marinette said.

It was a mark of how far gone they both were that neither asked why they were going to a hotel. Instead, Alya said, "I could take my pants off too."

"You absolutely will not!" Marinette exclaimed. She grabbed Alya's wrists and yelped when Nino lurched against her back.

"I'm going commando," Nino said in Marinette's ear, which was _way_ more than Marinette wanted or needed to know.

Alya's eyes dilated. "I could pull _your_ pants down and sit on your -"

"OKAY!" Marinette practically screamed. "Don't make me pour a glass of cold water on you two. So help me, I will do it!"

They both blinked at her. 

Her phone beeped.

"Thank god," Marinette said, grabbing it. The text was from Adrien, confirming where they were heading. She typed a quick answer and then grabbed Alya's and Nino's hands, roughly yanking them along behind her.

The remaining seven minute walk was torture. Marinette was seriously considering burning her ears off by the time they made it into the hotel. She hauled them both into the elevator and practically broke down into relieved tears when the doors opened on the fifth floor to reveal Adrien.

"My Lady?" he asked.

"Take this," Marinette said, shoving Nino at him. 

Adrien caught Nino effortlessly. "Hard time?"

"I am not in the mood for puns," Marinette growled, dragging Alya down the hall.

Inside the safety of the hotel room, Marinette made Alya sit on the bed while Adrien got Nino to sit in a chair across the room. The distance seemed to help, as Alya actually focused on Marinette for the first time in a while.

"Marinette, what's going on?" she asked, sounding scared. 

"Alya, I -" Marinette wrung her hands together and exchanged a look with Adrien. He came closer to her and wrapped his arms around her from the back, resting his chin on her shoulder.

"You guys remember a few months ago, you were really confused by how Marinette and I got so close so suddenly and we couldn't give you a straight answer?" he asked.

"Yeah, of course," Nino said. "I had to listen to Alya's increasingly bizarre theories."

Adrien nodded. "It's because we found out a secret about each other. A big one. One that we couldn't tell anyone else, but which we have to share with you now."

"What?" Alya said, eyes darting between them.

Marinette pointed to herself. "Ladybug." She pointed to Adrien, and then to Alya and Nino in turn. "Chat Noir. Rena Rouge. Carapace."

There was silence for approximately ten seconds, and then Alya screamed.

"You - and you! How - you - HOW -"

"I know it's a big shock," Marinette said quickly.

Alya looked at her in disbelief. "A big shock?! That's the world's biggest understatement. Why didn't you tell me?"

"We couldn't," Adrien said, his arms tightening a little. "It was too dangerous. Hawkmoth could’ve found out out."

"Wait," Nino said. "If it was too dangerous then, why are you telling us now?"

"Um," Marinette said.

"Well," Adrien said.

"You see," Marinette said.

"The thing is," Adrien said.

"Marinette!" Alya said.

"You're going into heat," Marinette blurted out.

Alya paled. "What?"

"What?" Nino said at the same time.

"It's... it's a thing. It has to do with the animal characteristics of your kwami," Adrien explained. "Mari and I went through it too." He nuzzled against her like the big silly kitty he was, and Marinette melted into him. She was so grateful for his presence.

"But I've only been Carapace like three times!" Nino said. "And Alya's… Alya’s only been Rena Rouge like five times."

"Apparently it only takes once," Adrien said.

Nino put his hands to his head. "What exactly does being in heat mean?"

"You're going to want to have a lot of sex for like a week," Marinette said.

"A week?!" Alya repeated.

"Well, maybe just a few days. Your bond wouldn't run as deep as ours does," Adrien said.

"A few - oh my GOD." Alya fell backwards, her arms outstretched. Her breasts bounced. Nino's jaw snapped shut and he stared at her, mesmerized.

Marinette glanced over her shoulder at Adrien. Time to go.

"I paid for the hotel room for four nights," Adrien said.

"Nino, you can tell your family you're staying with Adrien," Marinette said.

"And Alya, you can tell your family you're staying with Marinette. We'll cover for you," Adrien said. They'd be lucky in that respect.

"We got you condoms. Please glove up," Marinette said.

Alya sputtered. Nino blushed.

"Okay, bye! Have fun! Send a text so we know you're not dead!" Adrien literally picked Marinette up with one arm and grabbed the door hand with his free hand, launching them out of the room. The last thing Marinette saw was Nino stalking across the room towards the bed.

"That was possibly the most awkward conversation I've ever had," Marinette mused as her boyfriend carried her towards the elevator. "I think I need to go boil myself and bleach my brain."

"On the bright side, Alya couldn't freak out about you being Ladybug," Adrien said helpfully.

"That is a silver lining. I just feel so terrible."

They entered the elevator. Adrien set her down and hit the button for the lobby. "It's not your fault. Even Plagg and Tikki couldn't have known for sure. You know that kwamis have no way of knowing which of their characteristics will cross over. It just so happened that Alya and Nino got heat too."

"It's just... scary," Marinette said. "I remember."

Adrien sighed and wrapped her up in another hug. "I know. I was scared too. But... I think Alya and Nino will get through this."

Marinette hugged him back and smiled slightly. "At least they've had sex before."

"Are you saying you didn't like losing your virginity on a rooftop?" Adrien was trying to sound indignant, but he was smiling too widely to be effective. Marinette made a face at him and gently booped his nose.

"It was alright. I like your shower better."

He cocked his head. "You have amazing taste, Bugaboo. Let's go visit my shower right now."

"What about school?" Marinette said.

His sexy smile made her shiver as he said, "I can make you forget all about Alya and Nino."

"Bring it on, _Chaton_ ," Marinette said, winding her arms around his neck. She touched her lips to his jaw and felt more than heard the rumble that went through him. As the elevator doors opened, he scooped her up in a princess carry and made a beeline out of the hotel.

**Author's Note:**

> Find me on [tumblr](http://tsuki-chibi.tumblr.com/).


End file.
